Echegoyen International Symposium (8th Intl. Symp. on Synthesis & Properties of Nanomaterials for Future Energy Demands)

Electron donor-acceptor hybrids comprised of single-wall carbon nanotubes (SWCNT) are promising functional structures having direct applications in energy conversion schemes and molecular optoelectronics.^1-3 For building such hybrids and exfoliation of SWCNTs, the pi-stacking ability of large aromatic compounds such as pyrene is one of the commonly employed approaches. Often, the desired donor or acceptor entities are functionalized to carry one or more pyrene entities and allowed to interact with CNTs. As a suitable electron donor, BODIPYs stand out owing to their ease of structural modifications and rich spectral and redox properties. Consequently, several donor-acceptor conjugates comprised of BF2-chelated dipyrromethene, BODIPY, and the well-known electron acceptor, C60 have been developed. In the present study, we have newly synthesized a nano tweezer comprised of covalently linked BODIPY-C60 carrying two pyrenylstyryl arms. Compound 1 is further allowed to interact with SWCNT(6,5) and SWCNT(7,6) to form the supramolecular C60-BODIPY-SWCNT triads. Upon spectral, electrochemical, and computational characterization, pump-probe spectroscopic studies covering a wide femto-to-millisecond time scale have been performed to establish the occurrence of photoinduced charge separation.⁴ The presence of CNT prolonged the lifetime of the charge-separated states revealing the success of the present molecular design strategy for energy harvesting applications.

Following a brief introduction about the background and some personal details, a scientific history of the research work during the years will be presented along the method used to approach new and emergent areas. A scientific timeline will be presented starting from early academic career to the most recent activity and covering many research fields  from supramolecular chemistry to fullerene electrochemistry and endohedral fullerene structures. Life learned lessons  will also be described.

The electrocatalytic properties of some fullerenes, particularly for hydrogen evolution reactions (HER), were recently studied and predicted by computational studies. The catalytic performance of the most common fullerenes is deficient compared to other carbon-based nanocatalysts. Here, for the first time, we provide insights into how functionalization can alert the electron density on the carbon cages of the
fullerenes and influence the highly purified C₆₀ compounds to achieve better hydrogen oxidation reaction (HOR) activity using a combination of experimental and theoretical approaches. The bis-pyrrolidine hexa-adducts of the C₆₀ compound exhibited remarkable HOR catalytic activity of metal-free catalyst with a current density of 4.1 µA/cm² and mass activity of 27 A· mg_-1 at 0.4 V at room temperature. These results further demonstrate the relevance of such novel molecular catalysts for developing new HOR catalysts for fuel cell applications.

Understanding of chemical behaviour of actinide elements is essential for the effective management and use of actinide materials. However, actinide structural chemistry is challenging from the perspectives of both experiments and theories. To date, some of the important actinide bonding motifs, such as actinide-actinide metal-metal bond and actinide multiple bond, can only be obtained in the unstable clusters in gas phase. The hollow internal cavity of fullerene buckyballs has been known to be able to encapsulate novel metallic units, especially those otherwise very reactive or virtually impossible to prepare clusters. In this talk, we will present our recent studies of novel actinide endohedral fullerenes, focusing on their unique bonding behaviors. We found that unprecedented actinide metal-metal bond and actinide-lanthanide metal-metal bond can be formed and stabilized inside a series of dimetallic metallofullerenes, such as U₂@I_h(7)-C₈₀ , Th₂@I_h(7)-C₈₀ and ThLn( Ln= Y, Dy)@I_h(7)-C_2n. In addition, we obtained a series of stable molecule compounds which contains unique actinide bonds such as axial U=C bond and U≡C triple bond, enabling the experimental characterizations of these actinide bonds for the first time. These research results provide new perspective to the study of actinide bonds and endohedral fullerenes.

For almost two decades, intensive work from experimental and theoretical groups has made it possible to advance in the understanding of structural and electronic properties of endohedral metallofullerenes and cluster metal fullerenes. Hence, several groups have proposed diverse rules related with the relative stability of fullerene cages.[1] All of them considered the potential energy when they predict the stability of IPR and non-IPR isomers based on the ionic model, in which the guest transfers usually between three and six electrons to the hosting carbon cage. Those guidelines have explained why the highly symmetric C80(Ih) cage is the preferred fullerene when there is a transfer of six electrons, like in the well-known Sc3N@C80,[2] or in many other examples, such as Lu3N@C80, La2@C80, Y3@C80, etc.[3] In endohedral fullerenes with four or less electron transfer between host and guest, there is not a prevalent structure, like C80(Ih), and the diversity of captured carbon cages is larger, the theoretical prediction of the most abundant species to be formed in a K-H reactor being much more difficult. In addition to the relative potential energy, it is also necessary to consider the enthalpic and entropic contributions to the stability of the endohedral fullerenes. A systematic theoretical analysis for a series of A@C2n fullerenes with A = Th and U, in combination with accurate experimental characterization, have allowed us to show that the structures of A4+@C2n4- species are different from those of cluster fullerenes, such as Sc2O4+@C2n4-, Sc2S4+@C2n4-or Sc2C24+@C2n4-.[4] Here, we will present some of the most recent studies carried out in collaboration with Prof. Luis Echegoyen concerning to stabilization of non-IPR, formation of strong covalent actinide-actinide bons and electrochemical reactions in endofullerenes.[5]

The ability to easily and cheaply transport CO₂ from point-sources, such as power plants, to multiple, potentially distant, utilization sites of widely varying scales will enable wider utilization of carbon capture (CC) from flue gas. In the case of algal biomass cultivation, the use of carbonate sorbents for CC, transport, and delivery to algae has the potential to 1) eliminate the requirement for co-location of algal production facilities with power plants or costly, low-volume pipelines, 2) develop a means of inorganic carbon transport, storage, and delivery tuned directly to seasonal and daily algal productivity levels, and 3) reduce CC costs. Directly delivering CO₂ from the sorbent to algae avoids the need for a desorber and compressor in the CO₂ capture system, thus eliminating up to 90% of the energy use and ~60% of the capital cost of a typical capture system.

Lawrence Livermore National Laboratory has developed advanced manufactured composite sorbent materials that captures CO₂ as sodium bicarbonate, encapsulated within a CO₂-permeable polymer to increase the surface area and improve carbon capture rates by an order-of-magnitude compared with carbonate solution. In collaboration with Sandia National Laboratories, we have demonstrated the biocompatibility and ability of these composite sorbents to deliver CO₂ and control the media pH in algal cultures up to 100L. In collaboration with University of Arizona and Southwest Technologies LLC, we are now scaling up the composite sorbent material synthesis and integrating our CC system with a natural gas flue gas stream, coupled with a delivery system to 1000 L algal pond to perform 30-day continuous tests (Figure 1).

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. (LLNL-ABS-854252)

In the past two decades, various cycloaddition reactions to modify fullerenes have been developed as highly robust, modular, and functional-group-tolerant methods, including the Diels-Alder cycloaddition, Bingel-Hirsch cyclopropanation, Prato 1,3-dipolar addition, diazoaddition, benzyne addition, etc. To a large extent, the reactions on endohedral metallofullerenes (EMFs) mirrored these reactions. Fullerenes and EMFs are typically electron acceptors in these nucleophilic additions. The reactivity and regioselectivity are highly similar, which brings consistency but also limitations. First, certain fullerenes (e.g., C₆₀) are reactive in many reactions, but relatively electron-rich species, such as EMFs, often require harsh conditions, more equivalents of small-molecule reactants, and even so may still have low yields, and sometimes, no reaction. Moreover, in the small-molecule reactants, if there are electron withdrawing groups (EWG) affecting the reaction site, the reaction is difficult. Meanwhile, from a regioselectivity point of view, when other factors are comparable the electron-deficient bonds tend to react which limits the feasibility to regioselectively functionalize an electron-rich bond.
Here we report a new inverse electron demand Diels-Alder (IEDDA) reaction in which the fullerene and EMFs are electron donors, and the diimines, analogue of dienes, are the electron acceptors. In the IEDDA reactions, diimines were generated in-situ with an oxidizing agent, such as PbO2. Contrary to the trend in most fullerene additions, the diimines with electron withdrawing groups show higher reactivity. On C₇₀, the unusual cc-[5,6] adduct was the major product. Metallofullerenes Sc₃N@C₈₀ and Lu₃N@C₈₀ show higher reactivity than empty fullerenes C₆₀ and C₇₀. The adducts were characterized by single crystal structures and were found to be [5,6] adducts. Moreover, the reaction on EMFs were reversible, providing a new approach for chemical separation of EMFs.

The aqueous hybrid supercapacitor (AHSC) based on ammonium ion (NH₄⁺) is an interesting energy storage device with excellent properties. However, the scarcity of appropriate and effective cathode materials limited its practicality. Two-dimensional (2D) transition metal nitrides, carbides, and/or carbonitrides (MXenes) show potential as cathode materials, but their low capacitance also limits their applicability. Here, we synthesized N-functionalized 2D MXene (Ti₃C₂T_x) with Ti₂N interface engineering (Ti₂N/Ti₃C₂T_x), which displayed not only superior capacitance and rate capability but also a cycling stability then pristine Ti₃C₂T_x. Ex-situ XRD and XPS were used to study the fast transport of electrons/ions and its charge storage mechanism at the interface of Ti₂N/Ti₃C₂T_x. Furthermore, density functional theory (DFT) calculations were employed to validate the superior conductivity at the interface of the Ti₂N/Ti₃C₂T_x(T_x = OH) electrode. Moreover, AHSC was assembled with the Ti₂N/Ti₃C₂T_x as cathode and activated carbon as anode possesses outstanding energy storage performance. This study not only elucidates the charge storage process of Ti₂N/Ti₃C₂T_x but also provide new insights for designing novel cathode materials for energy storage devices. 

π-Organic diradicals are molecules with two unpaired electrons which emerge from the total or partial rupture of a chemical bond, typically a π-double bond.¹ Such unpaired electrons are stabilized by delocalization over the π-system and, to some extent, remain chemically inert. This allows the possibility to exploit these new chemical species with broken bonds in organic electronic applications.² In this contribution, we will describe the electronic structure of such organic diradical molecules and will address the key points that allow their implementation in organic field effect transistors devices,³ in photonics, in thermoelectric or thermopower applications.⁴

The goal of our studies is to apply carbon nanostructures, referred to as multi-layered fullerenes or carbon nanoonions (CNOs), for the controlled organization of resins [1], polymeric chains [2],[3] or triazines [4],[5], which, as a consequence, are a significant force for the ordered organization of pores within the synthesized materials. The critical role of using CNOs to design nanocomposites is in achieving high-quality modification of the 3D architecture and organization of the porous structure in such a way that the obtained materials possess an orderly distribution of pores and a homogenous pore size distribution (micro, meso and macro). The presence of micropores in porous materials results from the surface properties of the carbon nanoparticles. Bigger pores, such as meso and macropores, arise mainly from crosslinking of the oligomeric/polymeric chains or triazines. Incorporating functionalized CNOs leads to organized polymerization or formation of triazine skeleton in a three-dimensional manner. Therefore, the suitable choice of substrate structure enables further control of the meso and macroporosity of the porous nanocomposites. These parameters can be consciously controlled by selecting appropriate components and their percentage composition in the final mixture. A synergistic effect of both components may be observed, creating a material with new and unusual porosity superior to using one type of pore.
The best electrochemical performances were obtained when using the nitrile-functionalized pyrrolo[3,2-b]pyrrole unit to form triazine rings. The synthesis relies on forming a triazine ring as a covalent bond between organic building blocks to achieve covalent triazine-based frameworks (CTFs) with specific diameters forming a porous framework. CTFs constitute an emerging class of high-performance materials due to their porosity and the possibility of structural control at the molecular or atomic level. However, using CTFs as electrodes in supercapacitors is hampered by their low electrical conductivity and a strong stacking effect between adjacent CTF sheets. Therefore, we covalently immobilized triazine-based structures on CNOs to organize pores three-dimensionally.
Combining CNOs with the triazine framework produced a material with unique physicochemical properties, exhibiting the highest specific capacitance value of 638 F/g in aqueous acidic solutions. It should be emphasized that the specific capacitance value for hybrids was 1.5-2 times higher than that for the CTF reference. We examined the factors responsible for such a significant increase in electrochemical efficiency. This phenomenon is attributed to many factors. The material exhibits a large surface area, a high micropore content, a high graphitic N, and N-sites with basicity and semi-crystalline character. Thanks to the high structural organization and reproducibility and remarkably high specific capacitance, these systems are promising materials for use in electrochemistry. For the first time, hybrid systems containing triazine-based frameworks and CNOs were used as electrodes for supercapacitors.
The studies were performed under the financial support of the National Science Centre, Poland, grants #2017/25/B/ST5/01414 and #2019/35/B/ST5/00572 to M.E.P-B.

While recent advances in functional materials increasingly involve the inclusion of metal-oxide domains [1], reproducibility problems inherent to their incorporation remain an often success-limiting challenge. In this context, molecular science could play a transformative role by using the tractability and versatile solution-state chemistries of well-defined molecular complexes to simplify device fabrication. This is demonstrated by using coordination complexes of structurally and electronically recognizable fragments of bulk metal oxides as versatile molecular "modules" for replacing the parent materials. For example, soluble hexaniobate complexed molecular fragments of cubic-spinel and monoclinic Co₃O₄ are highly active analogs of bulk cobalt oxide, with the HOMO and LUMO energies of the complexes, 1, closely matching those of the valence- and conduction-bands of the parent bulk oxides. Use of 1 as a tractable analog of cobalt-oxide nanocrystals is demonstrated by its deployment as a co-catalyst for the direct Z-scheme reduction of CO₂ by solar light and water [2]. Alternatively, complexed semiconductor cores can activate molecular polyoxoniobate cluster-anion ligands themselves as nucleophilic sites for CO₂ reduction. Although pure and functionalized solid-state polyniobates such as layered perovskites and niobate nanosheets are photocatalysts for renewable-energy processes [3], analogous reactions by molecular polyoxoniobates are nearly absent from the literature. Under simulated solar-light, however, hexaniobate cluster-anion encapsulated 30-Ni^II-ion "fragments" of surface-protonated cubic-phase-like NiO cores activate the hexaniobate ligands themselves. Photoexcitation of the NiO cores promotes charge-transfer reduction of Nb^V to Nb^IV, increasing electron density at bridging oxo atoms of Nb–&#m181;-O–Nb linkages that bind and convert CO₂ to CO. Photogenerated NiO “holes” simultaneously oxidize water to dioxygen. In related work, hexaniobate ligands are used to arrest the growth of metal-oxide NCs and stabilize them as water-soluble complexes. This is exemplified by hexaniobate-complexed 2.4-nm monoclinic-phase CuO NCs, whose ca. 350 Cu-atom cores feature quantum-confinement effects [4] that impart an unprecedented ability to catalyze visible-light water oxidation with no added photosensitizers or applied potentials, and at rates exceeding those of hematite NCs [5]. Together, the above findings point to polyoxoniobate-ligand entrapment as a potentially general method for harnessing the catalytic activities of semiconductor fragments as the cores of versatile, entirely-inorganic complexes.

Ammonium ion (NH₄⁺) based aqueous hybrid supercapacitors (AHSCs) are attracting attention due to their environmental friendliness and excellent electrochemical performance [1-2]. Two-dimensional (2D) transition metal nitrides, carbides, and/or carbonitrides (MXenes) are the best choice for AHSCs cathode materials due to excellent performance, but the self-stacking effect of two-dimensional materials limits their wide application [3]. To solve this problem, we propose to grow 2H-MoS₂ nanosheets on the surface of Ti₃C₂T_x MXene, constructing heterostructures at the interface (HS-2H-MS@MXene). On the one hand, 2H-MoS₂ nanosheets are evenly distributed and oriented perpendicularly to the MXene surface. This arrangement enhances the material's specific surface area, creating additional sites for NH₄⁺ to reach to the MXene bone. On the other hand, the interface between the two materials forms a heterostructure that effectively prevents the recombination of charge carriers and facilitates fast redox reactions. The results show that the HS-2H-MS@MXene single electrode has a batter capacitance of 722.13 F/g at 1A/g, surprising rate capability (61.6% at 20 A/g) and excellent cycle stability of 90.1 % (after 5,000 cycles at 10 A/g), outperforming 2H-MoS₂ and the pristine MXene. Using activated carbon (AC) as the anode to assemble AHSC (HS-2H-MS@MXene//AC), it provides aspecific energy of 51.1 Wh/kg at 750.6 W/kg. It maintains an ultra-high capacitance of 95.6% after 10,000 charge/discharge cycles. In addition, density function theory (DFT) results show that the HS-2H-MS@MXene (T_x=O) electrode possesses higher conductivities. The calculated band energies, adsorption energies (E_ads), and diffusion barriers proved the enhanced conductivities of the HS-2H-MS@MXene electrode. This study could potentially introduce a novel concept for the advancement of high-performance cathode materials in the context of AHSCs.

Carbon materials have played an essential role in the development of lithium-ion batteries enabling transformative technologies including portable electronics, remote sensors, flying cars and electric vehicles. To meet the growing demand of the energy storage market, next generation batteries must provide dramatically increased capacity and cycling life, operate reliably, fast and safe, at reduced size and weight. Carbon nanomaterials hold great potential in offering a viable solution to these challenges. This talk will discuss current trends in the design of graphene and carbon nanotubes for batteries with high energy and power densities with extended cycling stability. Engineering porous graphene structures with low tortuosity for fast ion transport and chemical modification of the graphene surfaces for increased lithiophilicity are industrially scalable strategies to increase capacity, improve cycle life while simultaneously enhance rate capability and eliminate dendrite formation in batteries.

This talk will report fundamental calculations and experimental studies for chemical bond formation of open-ended vertically oriented carbon nanotubes (CNTs) to copper metal surfaces.1 Chemical bonds, preferentially covalent, between metal atoms and functional groups (linkers) at the open ends of CNTs is highly desired in order to create a robust connection and anchoring the CNTs to macroscopic metal surfaces.2-3 In addition, a chemical connection between metals and CNTs is critical for wiring two metals through a single CNT.4-5 Unlike traditional methods that rely on synthesis, where good quality CNTs are grown directly on metal substrates at temperatures above 600 °C this method reports covalent bond formation at temperatures as low as 120 °C. The reported theoretical calculations demonstrate that C atoms on aminophenyl can form a bridge like covalent bonds with two adjacent Cu atoms on (100), (110), and linear bond on (111) Cu crystal lattice substrates. The aminophenyl of bonded carbon atom was employed as linker molecule to simulate intramolecular electron transport between chemically connected carbon nanotubes and copper metals in this carbon/metal hybrid materials. The strength of the bonding was experimentally evaluated by placing the hybrid (CNT/Cu) material in solution and exposing to bath sonication. To our surprise, the CNTs remained attached to the substrate even after 30 min sonication. In addition, adhesive tape was applied to remove the bonded CNT array from the metal surface. The area from where CNT arrays were removed revealed that some CNTs still remained attached to the copper surface, supporting the strong bonding to the metal. XPS, FT-IR, Raman analysis and scanning electron microscopy images support the formation of direct connections between the vertically aligned CNTs and the metal substrates. The reported covalent bond formation is expected to facilitate the application of CNTs in multiple fields such as biomaterials, electrocatalysis, sensor development and electronics.

In the last few years, the mechanical bond has been added to the chemistry toolbox for SWNT modification.^[1] In this presentation, I will first discuss the characteristics of the mechanical bond that make it appealing for SWNTs. I will then describe the potential advantages of making mechanically-interlocked derivatives of SWNTs (MINTs), as compared to covalent or classic supramolecular derivatives of SWNTs, and go on to explain our approach for the synthesis of MINTs.^[2,3] Finally, I will illustrate with examples how the making of MINTs can contribute to modifying the surface properties of SWNTs,^[4] modulating their electronic properties,[5] and linking them to functional molecular fragments.^[6,7]

In the 2D materials field, I will describe the covalent grafting of 2H-MoS₂ flakes on graphene monolayers embedded in field-effect transistors.^[8] A bifunctional molecule was used that features a maleimide and a diazonium functional group, known to connect to sulfide- and carbon-based materials, respectively. MoS₂ flakes were first exfoliated, functionalized by reaction with the maleimide moieties, then anchored to graphene through the diazonium groups. This approach enabled the simultaneous functionalization of several devices. The electronic properties of the resulting heterostructure are shown to be dominated by the MoS₂–graphene molecular interface.

I will also discuss the journey that has led to these results, including the development of a “click” chemistry reaction for transition metal-dichalcogenides,^[9-11] and insights into the covalent patterning of graphene.^[12-14]

Two-dimensional materials have interesting properties. Taking full advantage of their characteristics, surface functionalization may be required;
In this presentation, I will mainly focus on the functionalization of graphite, graphene, and transition metal dichalcogenides using molecules, though the concepts can also be applied to other 2D materials.
Nanostructuring is at the heart of all functionalization protocols that we develop because it opens new possibilities for control and functionality. A variety of scanning probe microscopy methods are used for visualization, characterization, and manipulation.
The first approach is based on molecular self-assembly at the interface between a liquid or air, and graphite or 2D materials [1].
A second approach is based on the covalent attachment of molecules on 2D materials via covalent chemistry. It will be demonstrated how top-down scanning probe microscopy and optical lithography can be used to structure such covalently modified surfaces in addition to bottom-up strategies that provide control on the density and layer thickness, as well as submicron to nanoscale nanostructure [2,3,4]. Covalently modified surfaces can for instance be implemented for sensing purposes [5].
A third approach does not focus on the functionalization of the surface, but uses the surface as a support for the in-plane covalent stitching of molecules, leading to the formation of on-surface 2D dynamic covalent polymers [6,7].
A variety of molecule-based functionalization strategies, and combinations thereof, lead to unique substrate architectures, as revealed by local scanning probe microscopies.

Since the isolation of the first endohedral metallofullerene (EMF) La@C₈₂,¹ intensive research has been devoted to this family of compounds that encapsulate metal atoms or clusters in their inner void space.² Exohedral functionalization of EMFs is a key step to obtain new materials for multiple applications. For instance, water-soluble gadofullerenes are used as powerful contrast agents in medicine.³ Derivatization has also become an essential tool to purify and separate fullerene mixtures.⁴ Cycloadditions as Bingel-Hirsch reaction, Prato reaction, Diels-Alder reaction, or carbene and benzyne additions were among the most used reactions, although multicomponent reactions have been also considered recently.⁵ Computational chemistry has helped so far not only to understand the regioselectivity of a wide variety of chemical functionalization on EMFs, but also to disclose in many cases their reaction mechanisms.⁶ We here will present an overview of our computational studies on the reactivity of EMFs and will focus on recent results on actinidofullerenes, a family recently isolated and characterized by the groups of Ning Chen in Soochow and Echegoyen at UTEP.⁷ In mono-actinidofullerenes, the actinide tends to have oxidation state +4, which involves an important metal-cage interaction with significant covalent contributions. This feature makes them different from lanthanofullerenes, where the metal is usually with oxidation state +3. Consequently, the electronic structure, properties as well as reactivity of actinidofullerenes are expected to be different compared to their lanthanide counterparts.

The formation of hybrid nanostructures in spintronic devices has been investigated as a response to specific needs especially in nanoelectronics or adjacent fields where combined optical and magnetic response to various excitations is required for various types of sensing. With the advent of high accuracy and high resolution fabrication technologies such as lithography, coupling phenomena at the nanoscale may become accessible. The integration of the magnetic and semi-conductor components adds new capabilities to the electronic devices. While spin phenomena have long been investigated within the context of conventional ferromagnetic materials, the study of spin generation, relaxation, and spin-orbit coupling in non-magnetic materials took off only recently with the advent of hybrid spintronics and it is here many novel materials and architectures can find their greatest potentials in both science and technology. Here we present initial approach to nanostructuring of hybrid patterned structures based on magnetic FePt-based bilayers, as well as their response to the optical excitation of magnetization, in view of potential applications as THz spintronic emitters. Indeed, spintronic THz emitters made of L1₀ phase ferromagnetic/non-magnetic bilayers, can exhibit spin-to-charge current transition, resulting in controlled and tunable THz pulse emission. This work is funded through National Recovery and Resilience Plan, research component I8 grant PNRR contract 47 / 2023, from Romanian Ministry of Research, Innovation and Digitalization.

Porphyrins are versatile macrocycles that fulfill vital functions in living systems; the property richness of porphyrins allows their exploitation in different application fields, and in my group we have been particularly interested in sensing applications [1]. Although it is true that monomeric porphyrins possess valuable properties, their self-assembly in sophisticated, size and shape-controlled suprastructures, conjugated with their integration with inorganic species to obtain hybrid materials, can significantly boost their potentialities, leading to advanced functional materials with improved properties. The deposition of layers of porphyrin-based materials onto the surface of different transducers [2], such as for example quartz crystal microbalances (QMB), has led to the preparation of sensor arrays successfully exploited in different application fields, such as environmental control, or medical diagnosis [3]. Furthermore, the implementation of elements of chirality on such systems widens their applicability to chiral discrimination, a challenging task for chemical sensors. Chiral porphyrin-based architectures can be obtained from either chiral or achiral platforms. The latest progress in the development of these hybrid systems will be presented and discussed.

Finding novel solutions to combat climate change is one of the most challenging and pressing issues the humankind is currently facing.[1] While the production of solar fuels is still at a low technology readiness level, solutions need to be shown now to authorities and general public so that quick adaptation to renewable energies is achieved. With some European countries forcing fossil fuels out of their economies, hydrogen is seen as a very promising solution to deliver zero emission transportation.[2]
In this presentation, I will give an overview of project SEAFUEL.[3] SEAFUEL aims to use the renewable resources across the Atlantic Area to power the local transport fleet and support the shift towards a low-carbon economy. This demonstration project is the first example of integrating the use of solar energy and seawater to produce green hydrogen. In addition, the green hydrogen will be used to power a fleet of vans and some fuel cell buses, used locally by our partner in Tenerife ITER, as well as regional bus operator TITSA.
In parallel to the technology developments, academic partners in Liverpool and Galway have worked on the development on new electrode materials to fabricate electrolysers capable to operate under low-grade water. The latest developments in the field are discussed to guide research into new selective and efficient water splitting catalysts [4].

The importance of charge transfer (CT) and charge transport (CTr) for supporting life on Earth and for making our modern ways of living possible cannot be overstated.¹ Concurrently, electric dipoles are everywhere and understanding how they affect CT and CTr is of principal importance for addressing medical challenges and controlling the functionality of a wide range of materials and devices.^2,3 Discussions of the idea about dipole effects on CT date back to the mid 20th century.⁴ Reported experimental evidence from the 1990s and 2000s demonstrated the importance of dipole effects on CT.^5-7 The dipole-generated localized electric fields modulate the electronic properties of the CT moieties. The notion for such effects focusses on dipole-induced changes in the reduction potentials of the acceptor and the oxidized donor, affecting the CT driving forces and thus, the Franck-Condon (FC) contributions to the CT kinetics. We recently demonstrated that to harness such effects, which are inherently enormous, (1) the dipoles should be placed as closed as possible to the electron donor and acceptor, and (2) the media polarity should be lowered.^8,9 Polar media, indeed, stabilize charged states and in general, enhances the rates of CT. Polar media, however, screen the field permeation and damps the dipole effect on the electron donor and acceptor. Using hydrocarbons as a medium, results in electron transfer rates along the dipole that are six times larger than the rates for the same system when in polar solvents, such as acetonitrile.⁸ The same localized field effects in non-polar medium completely shut down the electron transfer against the dipole. As important as the dependence of CT kinetics and thermodynamics on medium polarity is, the interfacial nature of electrode processes presents challenges for characterizing this dependence.^10,11 While the polarity that solvated species experience in the bulk of a electrolyte solution is readily attainable, it is still challenging to determine the polarity of the microenvironment at the electrode surfaces where the redox processes occur.¹² An increase in electrolyte concertation in organic solvents increases their polarity, which is opposite for aqueous solutions.^11,12 At the electrode surfaces, however, the increase rigidity of the double layer, especially under applied voltage, decreases the oreitnational polarization, which principally contributed to the dielectric constant of solvents with large dipoles.¹² That is, the polarity that CT species experience at electrode surfaces is smaller than that in the bulk of the solution. Global-fit analysis on the dependence of measured reduction potentials on the polarity of the solvent and the electrolyte concentrations offers a means for estimating the effective polarity that redox species experience at electrode surfaces.¹² Such electrochemical analysis improves not only the characterization of CT thermodynamics, but also the quantification of the dipole effects on CT, which has key implications for electronics, photonics and energy science and engineering.

In recent years, considerable research has been carried out exploring the potential of oxide glasses as cathode materials for solid-state batteries [1-3]. Among these materials, alkali-transition metal oxide (TMO)-phosphate-based glasses garnered significant interest due to their, stable frameworks, minimal volume changes, thermodynamic stability, and excellent alkali storage capacity. Furthermore, as consist of both alkali and TM ions, which can exist in various oxidation states, these systems can exhibit the mixed ionic-polaronic conduction mechanism. Such feature has proven to be highly effective in facilitating the intercalation and deintercalation of alkali ions. It is also crucial that cathode materials have high thermal stability, which can be improved by incorporating metal oxides, for instance Nb₂O₅, into their composition [4].

This talk will focus on the electrical properties of glasses from Na₂O-V₂O₅-Nb₂O₅-P₂O₅ system. By varying the concentration of V₂O₅ (10 and 25 mol%) in two series, we aim to examine how its content influences the electrical transport mechanism, permitting us to evaluate its possible polaronic contribution by utilizing Solid-state impedance spectroscopy (SS-IS). Obtained conductivity spectra are studied in detail using two model-free scaling procedures, namely Summerfield and Sidebottom scaling. The results reveal that glasses with lower V2O5 content (10 mol%) exhibit a purely ionic conduction mechanism, indicating that V₂O₅ does not contribute to electrical conductivity via a polaronic mechanism. On the other hand, for glasses with higher V₂O₅ (25 mol%) and low Nb₂O₅ (0 and 5 mol%) content, a mixed ionic-polaronic conductivity is observed with dominant polaronic contribution. Interestingly, with further increase in Nb₂O₅ above 10 mol%, there is a switch in conduction mechanism and ionic one prevails. These findings provide valuable insights into the mixed-conductive glass system and shed light on the roles of V₂O₅ and/or Nb₂O₅, showcasing the ability to fine-tune the mechanism of electrical conductivity by adjusting the content of oxide glass and its ratio. Lastly, obtained results will be compared with our recent studies of conductivity mechanism in glasses with various TMO and alkali ions [5] and pure polaronic glasses [6].

Layered two-dimensional (2D) materials interact primarily via van der Waals bonding, which has created new opportunities for heterostructures that are not constrained by epitaxial lattice matching requirements [1]. However, since any passivated, dangling bond-free surface interacts with another via non-covalent forces, van der Waals heterostructures are not limited to 2D materials alone. In particular, 2D materials can be integrated with a diverse range of other materials, including those of different dimensionality, to form mixed-dimensional van der Waals heterostructures [2]. Furthermore, chemical functionalization provides additional opportunities for tailoring the properties of 2D materials [3] and the degree of coupling across heterointerfaces [4]. In this manner, a variety of optoelectronic and energy applications can be enhanced including photodetectors, optical emitters, supercapacitors, and batteries [5-7]. Due to their unique physics, mixed-dimensional heterostructures also enable unprecedented electronic and quantum functionality to be realized including gate-tunable Gaussian heterojunctions, neuromorphic memtransistors, and high-purity single-photon emitters [8-10]. In addition to technological implications for electronic and energy technologies, this talk will explore several fundamental issues including band alignment, doping, trap states, and charge/energy transfer across van der Waals heterointerfaces.

In this communication, we would like to show two recent examples in our group in which we exploit the confined nanospaces purposedly created in two very different self-assembled structures to selectively host specific molecules.
The first case comprises tubular nanostructures with custom-tailored pores, which are assembled by coupling two cooperative supramolecular processes of different hierarchy and acting in orthogonal directions. Chiral cyclic tetramers are first formed from 4 monomeric π-conjugated subunits by H-bonding interactions between nucleobase directors. A proper monomer preorganization affords high chelate cooperativities in solution[1] and onto surfaces.[2] When these cyclic species are subjected to a supramolecular polymerization process, helical self-assembled nanotubes are formed via nucleation-growth cooperative mechanisms in organic solvents[3] and in water.[4] Interestingly, the inner pore of these nanotubes can be coated with functional groups of opposite solvophilicity to the external medium, so as to host molecules that show an affinity for this environment.
The second case consists of a novel kind of Zn(II)bis-porphyrin nanocages constructed by imine condensation under thermodynamic control. These cages have two main conformations, depending on the arrangement of the imine bonds, and can host a wide diversity of ditopic nitrogen ligands that fit into its relatively rigid nanocavity. Remarkably, the cage is also an excellent host for fullerene.

During my lecture, I will present our latest results (1,2) on characterising different types of solar cells from DSSC and  OPV to MAPI using advanced photo-induced time-resolved techniques. Using PICE (Photo-induced charge extraction), PIT-PV (Photo-induced Transient PhotoVoltage) and other techniques, we have been able to distinguish between capacitive electronic charge, and a larger amount of charge due to the intrinsic properties of the perovskite material. Moreover, the results allow us to compare different materials, used as hole transport materials (HTM), and the relationship between their HOMO and LUMO energy levels, the solar cell efficiency and the charge losses due to interfacial charge recombination processes occurring at the device under illumination. These techniques and the measurements carried out are key to understanding the device function and improving further the efficiency and stability of perovskite MAPI-based solar cells. Last, the advances in self-assembled molecules, as selective contacts, for perovskite solar cells will be shown. SAMs have been paramount to achieving high solar-to-energy conversion values and increasing the stability of perovskite solar cells. 

The design of supramolecular capsules with large cavities is attractive because they feature potential advantages as platforms to selectively bind large guests, such as fullerenes and Endohedral Metallofullerenes (EMFs).¹ Generally, the practical applications of EMFs are hampered by their limited availability. Furthermore, their chromatographic purification (HLPC) is very challenging  and in some cases it is not successful. Our group reported a porphyrin-based supramolecular tetragonal prismatic nanocapsule (1),² which features an internal cavity with size complementary and electrostatic relationship specific for a brand new family of Uranium-based EMFs.³ Nanocapsule 1 is able to sequentially and specifically recognize U₂@I_h-C₈₀ and Sc₂UC@I_h-C₈₀ among all those compounds present in the crude, simply by soaking crystals in a solution of the reaction crude. The stepwise and selective encapsulation of U-based EMFs allowed their separation and further purification by solvent-washing, obtaining highly pure fractions of the desired compounds in one step. Follow-up studies with U-based C₇₈ soots indicate that not only the internal clusterelectronics but also the shape of the carbon cages strongly influences the selectivity of the nanocapsule.

Taking advantage of the tight binding of fullerenes in our porphyrin-based supramolecular tetragonal prismatic nanocapsules, these are used as supramolecular shadow masks to tame the over-reactivity of Bingel-Hirsch-type cyclopropanation reactions and, more importantly, to have full control on the equatorial regioselectivity and on the number of additions.⁴ Thus, exclusively equatorial bis-, tris- and tetrakis-C₆₀ adducts using ethyl-bromomalonate are stepwise obtained and fully characterized (NMR, UV-vis and XRD). Furthermore, the regioselectivity control is finely tuned using a three-shell Matryoshka-like assembly towards the synthesis of a single trans-3 bis-Bingel-C₆₀ for the first time.⁵ These results, fully attributed to the confinement control imposed by the capsule’s cavity, represent a novel and unique strategy to infer regio-control to the synthesis of fullerene multi-adducts. We envision that the described protocol will produce a plethora of derivatives for applications such as solar cells.

Carbon nanotubes and graphene are almost perfect molecules with truly amazing combinations of thermal, electrical, and structural properties. However, to harvest their full potential they need to be fully integrated as hybrid materials in all sorts of matrices. Full integration requires their development beyond conventional composites so that the level of the non-nano material is designed to integrate fully with the molecules of carbon nanotubes and graphene. Here the nano materials are part of the matrix rather than a differing component, as in the case of conventional composites. To advance the development of multifunctional materials integrating nanotubes and graphene, this research is focused on the simultaneous control of the nano architecture, structural properties, the thermal and the electrical conductivity of fully integrated nano hybrid materials systems. These hybrid materials systems are designed to surpass the limits of rule of mixtures in conventional composite design. The goals are to implement multifunctional designs to fully mimic the properties of carbon nanotubes and graphene on larger scales, from the nano, to the meso, to the micro and to the macro scales, and to enhance the thermal and electrical the management, in addition to the control of other properties such as mechanical strength and fracture toughness. These new approaches involve exfoliation, functionalization, dispersion, stabilization, alignment, polymerization, reaction bonding and coating, designed to achieve full integration. Typical examples of structural applications of polymeric and ceramic matrices and applications in energy systems such as capacitors and batteries as well as other material systems are presented and discussed.

Inorganic fluorine-based compounds are found today as nano-components in many applications, including energy storage and conversion, photonics, electronics, medicinal chemistry, and more [1]. The strategic importance of nano-fluorinated materials can be illustrated by several examples drawn from various scientific fields. In the field of energy storage, fluorinated carbon nanoparticles (F-CNPs) are tested as active materials in primary lithium batteries, while 3d-transition metal fluorides and oxyfluorides, mainly iron-, cobalt- and titanium- based have been proposed as electrodes in secondary batterie(reversible) s. In all-solid-state batteries, materials derived from fluorite- (CaF₂) or tysonite- (LaF₃) structural types can be used as solid electrolytes, provided the F- anions are highly mobile. Nanocrystalline rare-earth fluorides are currently used for their photoluminescent properties at the micro- or nanoscale.
Functionalized nanoparticles and nanostructured compounds based on solid-state inorganic fluorides are used in many other advanced fields, including fluorinated graphene quantum dots (FGQDs), solar cells (DSSC, QDSSC), transparent conducting films (TCF), solid state lasers, nonlinear optics (NLO), UV absorbers, etc.
Their role is also decisive in medicine and biotechnologies [2], where doped rare-earth fluoride nanocrystals serve as luminescent biomarkers thanks to their up- and down-conversion properties, allow fluorine labeling of nanoparticles and in-vivo 19F NMR. Relevant nanotherapeutics include photodynamic therapy (PDT), luminescent thermometry, radiotracers for positron emission tomography (PET), theranostic nano-agents that incorporate both imaging probes and therapeutic media, and are therefore capable of carrying out both diagnosis and therapy within the same nano-object.
References

Proton Electrolyte Membrane Fuel Cells (PEMFCs) hold great potential as energy conversion solutions for stationary and transportation purposes. However, in order to compete with internal combustion engines, it is crucial to enhance their durability (1). This study delves into the advancements in membrane electrode assemblies (MEAs) for High-Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFCs). The HT-PEMFCs under investigation were operated within the temperature range of 160-170 °C, utilizing either pure humidified hydrogen or humidified reformate with varying compositions (2).
The elevated operating temperature of high-temperature PEM fuel cells (HT-PEMFCs) opens up new horizons, enabling the utilization of methanol or methanol-water mixtures as viable fuels for commercial fuel cell systems. Remarkably, HT-PEM cells exhibit outstanding tolerance to CO impurities, surpassing 3 vol-% without experiencing substantial performance degradation. Additionally, their heightened resistance to H2S and SO2 poisoning significantly bolsters their operational efficiency, paving the way for improved energy conversion. Our research has unveiled the remarkable durability of HT-PEMFCs incorporating a thermally cross-linked m-PBI membrane. Over an extended period of 9,200 hours, these cells exhibited an impressively low decay rate of only 0.5 μV/h at 0.2 A/cm². The single cell performance has shown an exceptional stability over a span of 10,000 hours, with 9.3 μV/h degradation rate at a current density of 0.4 A/cm². These findings signify a significant stride towards attaining long-lasting and reliable HT-PEMFC systems.
Additionally, we have demonstrated that increasing the pressure of the incoming gases to 1.5 bar (abs) - as anticipated - leads to performance improvements. Preliminary results have showcased a power density of 0.5 W/cm² at 0.8 A/cm², highlighting the promising potential of this technology.
Our study involved rigorous continuous operation and over 1400 start-stop cycles to comprehensively analyze the degradation effects in HT-PEMFCs. The start-stop cycles revealed a degradation rate of 60 µV per cycle, as observed during current density cycling ranging from 0 to 400 mA/cm². These findings shed light on the impact of repeated start-stop events on the performance and longevity of HT-PEMFCs, providing valuable insights for further optimization and durability enhancement.
We continue improving our products (HT-PEMFCs), looking for innovative solutions to current limitations on HT-PEMFC durability.

In the present communication we will focus on the use of organic charge transporting materials that have synthesized in our lab and used to prepare Perovskite-based Solar Cells.^1,2
In our research group we have dedicated a great effort on the preparation and study of novel organic compounds for their incorporation in perovskite solar devices, either as hole or electron-transporting layers. Thus, we have reported the use of fullerenes^3,4 and NDIs⁵ as electron transporting layers in PSCs, to prepare efficient and stable devices. On the other hand we have prepared a great variety of hole transporting materials, including polymers,⁶ and Oligotryarylamine (OTA) functionalized with different cores such as HexaArylBenzene (HAB),⁷fullerene,⁸ or pillarene⁹ among others, to prepare highly efficient and stable in PSCs.

“Plastics are a large group of synthetic organic materials whose common quality is that they can be molded into desired shapes—and they are now everywhere.”….“But plastics are now most indispensable in health care in general and in hospitals in particular. Life now begins (in maternity wards) and ends (in intensive care units) surrounded by plastic items made above all from different kinds of PVC: flexible tubes (for feeding patients, delivering oxygen, and monitoring blood pressure), catheters, intravenous containers, blood bags, sterile packaging, trays and basins, bedpans and bed rails, thermal blankets.” [1]
At the beginning of the XX century, with the exception of diamond, materials science was absolutely dominated by inorganic solids. This was the case, even though Bakelite had been patented in 1907. By mid-century organic engineering materials were rapidly finding applications as phone housings and radio housings, pens, mechanical pencils, circuit boards, etc. A whole art deco field in the arts, crafts and architecture was fueled by plastics from the 1920’s on. [2] Toward the end of the XX century, implements that relied solely on cement and metals, such as airplanes, automobiles and vehicle bridges were being made out of plastics (thermosets) and even recycled plastics. [3].
The subtler area of materials science, electronics, was governed by silicon and, to a lesser extent, germanium. Organic electrical conductors were slowly being developed towards the end of the century, receiving a strong impetus with the appearance of organic metals, superconductors and semiconductors, as well as the preparation of polyacetylene and other semiconductor polymer films and the discovery that they could be coaxed to increase their conductivity upon oxidation or reduction (doping). [4]
In this presentation the emphasis will be on the electrical conductivity of organic materials and their technological applications such as light emitting diodes, photovoltaics, thermoelectrics and batteries.

“Plastics are a large group of synthetic organic materials whose common quality is that they can be molded into desired shapes—and they are now everywhere.”….“But plastics are now most indispensable in health care in general and in hospitals in particular. Life now begins (in maternity wards) and ends (in intensive care units) surrounded by plastic items made above all from different kinds of PVC: flexible tubes (for feeding patients, delivering oxygen, and monitoring blood pressure), catheters, intravenous containers, blood bags, sterile packaging, trays and basins, bedpans and bed rails, thermal blankets.” [1]
At the beginning of the XX century, with the exception of diamond, materials science was absolutely dominated by inorganic solids. This was the case, even though Bakelite had been patented in 1907. By mid-century organic engineering materials were rapidly finding applications as phone housings and radio housings, pens, mechanical pencils, circuit boards, etc. A whole art deco field in the arts, crafts and architecture was fueled by plastics from the 1920’s on. [2] Toward the end of the XX century, implements that relied solely on cement and metals, such as airplanes, automobiles and vehicle bridges were being made out of plastics (thermosets) and even recycled plastics. [3].
The subtler area of materials science, electronics, was governed by silicon and, to a lesser extent, germanium. Organic electrical conductors were slowly being developed towards the end of the century, receiving a strong impetus with the appearance of organic metals, superconductors and semiconductors, as well as the preparation of polyacetylene and other semiconductor polymer films and the discovery that they could be coaxed to increase their conductivity upon oxidation or reduction (doping). [4]
In this presentation the emphasis will be on the electrical conductivity of organic materials and their technological applications such as light emitting diodes, photovoltaics, thermoelectrics and batteries.

The 19th century is often referred to as the age of iron, the 20th century as the age of silicon, and the 21st century as the age of carbon. In this century, from the perspective of environmental conservation and economic security, research on harnessing natural energy is becoming increasingly important. In this presentation, we will introduce a new organic solar cell that actively employs nanocarbon materials, which are anticipated to be a groundbreaking next-generation solar cell.
Electron transport layers employing vacuum-deposited fullerene derivatives, properties of carbon nanotube thin films created through wet and dry processes and their applications to bottom and top contact electrodes respectively, and hole transport materials using carbon nanotubes are discussed. This paper presents organic thin-film solar cells and perovskite solar cells that utilize these functionalized nanocarbon materials.

Perylenediimides (PDIs) are highly stable and versatile dyes, which have been widely used as electron-acceptor moieties in the construction of systems for artificial photosynthesis or for optoelectronic applications, including solar cells [1].
On the other hand, azobenzenes are very well-known molecules, characterized by its photoinduced trans-cis isomerization process, which is reversible either by light (with a different wavelength from that of the initial reaction) or thermally in the dark. This property, together with their photostability, turns them into ideal entities for various molecular devices, specifically as light triggered switches [2].
Recently, we have initiated the photophysical study of PDI-azobenzene ensembles obtaining exciting results [3]. Herein, we will present the extension of these studies to include phthalocyanines into the equation, as they are robust materials with excellent electron donor characteristics [4].

Conventionally, noble metal nanoparticles, such as gold are synthesized using a reducing agent like sodium borohydride (NaBH₄) or sodium citrate at elevated temperatures and alkaline pH, with stabilizers added to control the size and dispersion of the nanoparticles [1]. While sodium citrate is sometimes used as a single reducing and stabilizing agent, it is limited in the range of gold nanoparticle sizes that can be obtained [2]. Fullerenes and polyhydroxy fullerenes have been coated on gold nanoparticles as they can impart excellent electronic properties in addition to providing stability [3, 4].
We have discovered that polyhydroxy fullerenes (PHF) can act as a single reducing and stabilizing agent by simple mixing of the gold chloride with PHF at room temperature [5]. The gold nanoparticles obtained are monodisperse as characterized by dynamic light scattering and high resolution-transmission electron microscopy. The size of gold nanoparticles is controllable by changing to ratio of reactants and range from 1 nm gold nanoclusters to 100 nm nanoparticles. We studied the mechanism of nanoparticle formation with PHF and proposed a three step process. In the first step, electrostatic attraction between negatively charged PHF and gold cations lead to formation of agglomerate. In the second step, PHF reduces gold cations and formation of Au-O-PHF bonds were detected by electron energy loss spectroscopy and x-ray photoelectron spectroscopy. In the third step, agglomerates containing gold nanoparticles disperse to yield monodisperse colloid. The gold nanoparticles obtained with method is stable for at least 2 years.
The novel PHF-mediated synthesis method can also be applied to other noble metals. The surface PHF coating on noble metal nanoparticles integrates the properties of both metal and carbon nanoparticles, resulting in superior functional applications. Our findings open up new opportunities for metallic nanoparticle preparation methods, properties, and applications.

The activation of small molecules play an important role to towards more sustainable chemical processes. Renewable solar and wind resources can provide the energetic driving for such reactions, leading to electrocatalytic transformations. Here, I will present our research on the cathodic, reductive activation of O₂, N₂ and CO₂ using trimetal substituted polyoxometalates as active site functional mimics of redox metalloenymes. Second, I will present the use of metal guest-Keplerate host supramolecules as inorganic analogs of redox metalloenyme assemblies.

Cathodic activation of O₂: Paradoxically, nature’s monooxygenase enzymes activate O₂ typically via a two-electron reductive pathway. Both Fe and Cu-based catalysis using reducing agents under protic conditions is known, but surprisingly, cathodic electrocatalysis using H₂O as a proton and electron source is almost unreported. Recently, we found that iron Keplerates, {Fe₃₀W₇₂} can be used as electrocatalysts for the oxidation of light alkanes and alkenes in water.[1] Mechanistic studies have revealed that reaction intermediates have reactivity profiles similar to those observed for Compound I of cytochrome P-450.[2] More recently, we have also found that tetra-Cu Weakley polyoxometalates also are also very efficient electrocatalysts for the cathodic activation of O₂ and show reactivity profiles similar to those of the iron Keplerates.

Reduction of CO₂ to CO: The removal of CO₂ from the atmosphere through is capture or sequestration is a feasible technology, however, is not sustainable due to the high cost of the process and the low value of captured CO₂requiring the transformation of CO₂ to a higher valued products. Therefore, we have prepared a series of trimetallo substituted polyoxometalates that on the one hand can catalyze the reversible reduction of CO₂ and oxidation of CO,and on the other hand can be tuned to reduce CO₂ with very low overpotentials.[3]

Reduction of N₂ to NH₃: The electrification of ammonia synthesis is a key target for its decentralization and toward lowering the impact of chemical processes on atmospheric carbon dioxide concentrations. Using catalyst a tri-iron substituted polyoxotungstate, {SiFe₃W₉} in the presence of either Li⁺ or Na⁺ cations as promotors through their binding to {SiFe₃W₉} we show that in an undivided cell electrolyzer, rates of NH₃ formation was at up to 1.15 nmol sec^–1 cm^–2 with moderate faradaic efficiencies of ~25%. Based on an assumption of arbitrary 10% catalyst coverage on a Cu foil cathode, a TOF of 64 sec^–1 was calculated. 

Iron-nickel guest-{Mo₆₀W₇₂} host supramolecules as an inorganic functional mimic of a hydrogenase enzyme: Can soluble inorganic metal oxides and the related guest-host complexes with encapsulated transition metals incorporated through assembly reactions, act as functional analogues of redox metalloenzymes that carry out multielectron transformations of small molecules? Here we show, that Fe-Ni assemblies bound to mercaptopropionate lignads within {Mo₆₀W₇₂} acts as a hydrogenase enzyme complex electro- and photoelectrochemically (PEC) forming hydrogen from protons and electrons. Reactions rate comparable to those found in the wild type enzyme are observed with very high faradaic efficiency under PEC conditions.

Metal single atoms in nitrogen doped carbon materials (M-NC) have attracted plenty of attention during the last decades in the field of electrocatalysis for oxygen reduction and carbon dioxide conversion amongst others. In the cathode of proton exchange membrane fuel cells Fe-NC are the most promising solution to scarce and expensive Platinum-group-metal catalysts,[1] and in the cathode of CO₂ conversion electrolysers, Fe and Ni-NC are predicted to be as active as Au or Ag.[2] However, their controlled synthesis and stability for practical applications remains challenging. Approaches to enhancing their catalytic performance include increasing the loading of Fe single atoms, for example by decoupling high temperature pyrolysis and Fe coordination atoms, or enhancing the intrinsic activity of the FeN_x sites, for example by engineering of coordination environment or creation of dual atom catalysts.[3–5] However, the metal utilization within these materials remains very low owing to the lack of scaffolds that combine adequate micro- and mesoporosity.
In this work we employ inexpensive 2,4,6-Triaminopyrimidine (TAP) with MgCl₂.6H₂O as porogen to prepare a highly porous N-doped carbon material.[6] The hydrogen bonding between nitrogen moieties of TAP and the water molecules of the Mg salt allows an optimal interaction during pyrolysis that leads to remarkable porosity in the nitrogen-doped material (~3300 m² g^-1) and very available N sites for Fe or Ni coordination. The subsequent low temperature metal coordination (Figure 1) results in a highly active O₂ reduction to electrocatalyst with a mass activity 4.0 A g^-1 at 0.8 VRHE in acid electrolyte, and one the highest turnover frequency for CO₂ reduction reported to date for M-NC materials.[7] Additionally in-situ nitrite stripping reveals a high active site density of >2×10¹⁹ sites g^-1; and a electrochemical active site utilisation of 52% and 76% for Fe and Ni-NC, respectively, up to our knowledge the highest reported to date. Aberration corrected high-angle annular dark field scanning transmission electron microscopy, time-of-flight secondary ion mass spectrometry, X-ray absorption extended fine structure and density functional theory calculations were employed to assess the electrochemical stability and the intrinsic activity of the active sites.

Defects in solids, including semiconducting single-walled carbon nanotubes, have recently gained significant interest as atomic traps for electrons, excitons, and their quantum coupling. The covalent bonding of organic functional groups to the sp2 carbon lattice creates molecularly tunable sp3 quantum defects with unique properties and potential applications in various fields. Unlike native defects, which usually quench exciton photoluminescence, synthetic defects in single-walled carbon nanotubes fluoresce brightly in the shortwave infrared, producing single photons at room temperature. Known as "organic color centers," these quantum defects have opened up exciting opportunities for researchers in chemistry, physics, materials science, and biomedical engineering. In this talk, I will discuss recent progress in this emerging field of synthetic quantum defects, focusing on the unique properties and potential applications of organic color centers in semiconducting single-walled carbon nanotubes. The talk will highlight the exciting opportunities these quantum defects offer and will provide insight into the rapidly expanding research and applications of these fascinating quantum systems.

Rare-earth permanent magnets have a  broad range of applications, in motors of electric and hybrid cars, in wind turbines, and  in any machine where efficiency is important [1].  Many countries are establishing    rigorous standards for electric motors efficiency, as IE4 and IE5 [1,2].

A rotating machine as an  electric motor has two main components: a rotor and a stator.    In essence, by using  a permanent magnet in the rotor, the efficiency of the machine can be increased. This save an energy that would be used to magnetize the rotor. This also makes possible that the motor can be of the brushless type, thus avoiding friction.

In the electrical motors, the magnets need to present high resistance against reversal of magnetization. The motor heats during the  motor operation.  As consequence, the magnets embedded in the stator also heats. There is much  research on  increasing motor efficiency [3], especially in the case of electric cars, where automony is an important issue, and where batteries are very expensive.

Nanocrystalline magnets display better resistance  against reversal of magnetization. Here this  subject is discussed by considering magnetostatic and  exchange energy terms.    

The mechanisms of reversal of magnetization in nanocrystalline permanent magnets are reviewed. Nanocrystalline Rare-earth magnets  can be  used in motors, or also in thin films [4]. Crystallographic texture effects on the coercivity are also discussed [5].

Our research group is interested in the application of supramolecular chemistry to understand and manipulate biology.[1,2] Our work philosophy is based in the importance of weak and non-covalent forces to control the shape and the topology of biomolecules, which are governed by the principles described by supramolecular chemistry. These supramolecular lessons can then be applied to control the properties and function of biomolecules. We believe that by modulating the shape we can mimic, control and improve functional behaviour. With focus in supramolecular interactions for artificial membranes and tubular composites, we investigate the construction of synthetic systems for controlling and emulating biology and life-like soft systems.[3-5]

Polymer mechanochemistry studies the interaction between mechanical force and polymer materials, in both fluid- and solid-state systems, through the development of so-called mechanophores.[1][2] The latter are chemical motifs that generate physicochemical signals in response to the cleavage of weak bonds, which may be covalent or supramolecular.[2] Some mechanophores exhibit the particularly attractive feature of being mechanochromic, meaning that they change their optical properties (absorption or emission of light) as a consequence of the force-triggered bond cleavage event.[3][4] This has paved the way for their use as force sensors to predict/anticipate the end-of-life or mechanical failure of polymer materials.[5]
This contribution will address covalent, heterolytic mechanophores, i.e., motifs that dissociate into ion pairs upon mechanical stimulation. This force-triggered bond cleavage mechanism has primarily been reported in solutions but is not often encountered in solid-state systems. Our group has recently provided the first example of a heterolytic mechanophore that can be mechanically activated in solid-state materials leveraging appropriately designed triarylmethane scaffolds (Tr). By performing uniaxial deformation experiments in conjunction with optical techniques in a home-built setup, we will show that the initially colorless Tr species dissociate into brightly colored, resonance-stabilized triarylcarbenium ions (Tr+)and anionic counterparts.[6] Additionally, the strong mechanochromic response can be easily tuned via simple structural modifications. The fundamental and applicative implications of our findings will be further discussed.

There has been significant interest in incorporating chromophoric compounds into optoelectronic applications based on metal-organic frameworks (MOFs). This approach has provided materials that can be easily integrated into devices, including photovoltaics, light-emitting diodes, and transistor-related applications.[1]
Phthalocyanines are a family of synthetic analogues of porphyrin compounds chemically and thermally stable, which makes them useful in applications that require robust materials. They are excellent electron donors, making them useful in optoelectronic devices.[2] Additionally, phthalocyanines can be easily modified by attaching different chemical groups to their periphery or to the axial position, which allows for fine-tuning of their properties. In this context, silicon phthalocyanines (SiPc), equipped with axial coupling groups, represent a good candidate to combine with metallic atoms, to afford MOF-based chromophoric assemblies, where the inter-linker and metal ion distances, as well as the overall geometry, are crucial parameters to tune the electronic coupling between MOF building blocks. Recently, we have shown that MOF thin films can be successfully assembled using SiPc as linkers, resulting in a porous material that can be used as an optical resonator.[3]
In this communication, we will present our recent advances on SiPc compounds, axially functionalized with carboxylic acid appends and peripherally substituted with different groups and the evaluation of their capability to generate, in combination with Zn atoms, optically active SiPc-based MOF thin films which show systematically tuned J-type electronic coupling.[4]

Knowing that solids are formed by atoms, and that atoms have, indeed, a size, it is no wonder that the size of atoms does influence the Chemistry of Solids. However, the way the atoms size makes its influence can be rather elaborate, even surprising¡. In the present lecture, after a brief introduction of atoms and ions sizes, we will present two examples of the marked influence of Rare Earth (RE) ions sizes in two very interesting cuprate families:
* The High Pressure/High Temperature Solid State Synthesis of Materials of the so-called rutheno-cuprate family: RuSr2RECu2O8 (The unexpected influence of the f-electrons)
* The presence, or absence, of superconducting properties in the family of partly substituted copper in YSrCuO: i.e. Mo0.3Cu0.7Sr2RECuO7+d. (Anion & cation order/disorder)
* The third example shows the correlation of P & T in the ordering in the A & B positions of a quadruple perovskite “Sr2RECu2IrO9-”.[3]

Carbon is the key to many technological applications that have become indispensable in our daily life. Altering the periodic binding motifs in networks of sp3-, sp2-, and sp-hybridized C-atoms is the conceptual starting point for a broad palette of carbon allotropes. The past two decades have served as a test-bed for measuring the physico-chemical properties of low-dimensional carbon with the advent of fullerenes (0D), followed in chronological order by carbon nanotubes (1D), carbon nanohorns, and, most recently, by graphene (2D). These species are now poised for use in wide-ranging applications.
Expanding global needs for energy have led to a significant effort to develop alternatives to fossil fuels. While alternative sources for energy are already in use, they comprise a small percentage of the energy demands needed to carry us through the 21st century. No single source will solve the global needs, but the development of photovoltaics has vast potential as a point-of-use power source. Recent work has shown that hybrid photoelectrochemical efforts with a percolation network of photon absorbers coupled to an electron/hole transporter in combination with advanced photon management are the ideal design for realizing breakthroughs in high photon conversion efficiencies suitable for the catalysis of water.
I will report on our efforts regarding a unifying strategy to use the unprecedented charge transfer chemistry of 0D fullerenes, the ballistic conductance of 1D carbon nanotubes, and the high mobility of charge carriers in 2D graphene, together in a groundbreaking approach to solving a far-reaching challenge, that is, the efficient use of the abundant light energy around us. For example, hybrid photoelectrochemical efforts with a percolation network of photon absorbers coupled to an electron/hole transporter in combination with advanced photon management are the ideal design for realizing breakthroughs in high photon conversion efficiencies suitable for the catalysis of water.

The great potential in modern photovoltaics of semiconductor kesterite Cu₂ZnSnS₄ warrants continuing interest by researchers in developing new synthesis routes and in studies of the fundamental and application properties of the compound. One of the overlooked kesterite features is its susceptibility to oxidation when exposed to air, which is of utmost interest in synthesis, examination, and storage/applications. In this regard, kesterite is a quaternary sulfide which exhibits a wide range of lattice and compositional defects while kesterite’s nanopowders are also characteristic of increased specific surface area. These factors can impact its oxidation reactivity, especially, in ambient air where the presence of water vapor is known to accelerate oxidation processes. 

Recently, we developed a few precursor systems for making kesterite via the mechanochemically-assisted synthesis method [1,2]. In all cases, the isolated raw powder is a cubic polytype of kesterite (tentatively called prekesterite) with no semiconductor properties. This variety is converted upon annealing in argon at 500 ºC to the tetragonal semiconductor kesterite. In this study, we prepared and investigated kesterite nanopowders (both cubic and tetragonal polytypes) from the metal sulfide (MS) system {Cu₂S+ZnS+SnS+S → Cu₂ZnSnS₄} and from the Zn/Sn copper alloys (CA) system {2Cu+Zn+Sn → copper alloys} that further reacted with sulfur in-situ towards kesterite formation {alloys+4S → Cu₂ZnSnS₄}. After characterization, all freshly made nanopowders were exposed to ambient air for 6 months.

The solid-state ⁶⁵Cu/¹¹⁹Sn MAS NMR study confirmed our earlier observations and neither ⁶⁵Cu nor ¹¹⁹Sn resonance signals were observed for the prekesterites from both systems [1,2]. It was true for the freshly made and air-exposed samples. This is ascribed by us to the so-called d₀ magnetism in such nanopowders. On the other hand, the annealed kesterite nanopowders clearly showed both these resonances as anticipated. For the fresh samples, the ⁶⁵Cu signals were found at 779.6 and 799.0 ppm and the ¹¹⁹Sn signals were found at -134.1 and -133.7 ppm for the kesterite nanopowders from the MS and CA precursor systems, respectively. For the samples being oxidized in air for 6 months, the signals could also be seen although with the relatively decreased intensities, respectively, for ⁶⁵Cu at 797.1 and 800.0 ppm, and for ¹¹⁹Sn at 134.1 and 134.3 ppm. This is an interesting observation since the XRD patterns for the oxidized nanopowders support there significant amounts of the hydrated copper and zinc sulfates with the former containing magnetically active Cu⁺² ions. Apparently, the presence of Cu⁺² in the aggregates of the copper sulfate, which are spatially separated from the kesterite particles, does not interfere with the overall advantageous NMR resonance conditions.

(NCN grant No. 2020/37/B/ST5/00151)

Subphthalocyanines (SubPcs) are well-known cone-shaped chromophores consisting of three 1,3-diiminoisoindole units assembled around a boron atom [1,2,3]. As a result of their 14 pi-electron aromatic core and their tetrahedral geometry, SubPcs exhibit outstanding physical and optoelectronic properties (e.g., strong dipole moment, excellent light absorption in the 550-650 nm, rich redox features, and excellent charge transport capabilities), that have been skillfully used in variety of applied fields, such as molecular photovoltaics, among others. SubPcs were used by us as non-fullerene acceptors in bulk heterojunctions (BHJ) solar cells. On the other hand as part of our systematic investigation in the preparation and study of novel SubPc-based D–A systems, we have used 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) as partner for SubPcs. Moreover, in the case of unsymmetrically substituted SubPcs (i.e., prepared by cyclotrimerization of a phthalonitrile with no C2v symmetry), they present inherent chirality and the corresponding couple of enantiomers can be isolated. Columnar aggregates based on chiral SubPcs have been also prepared, giving rise to ferroelectric self-assembled molecular materials showing both rectifying and switchable conductivity. These chromophores have been incorporated in multicomponent systems showing a panchromatic response and allowing the tuning and controlling intramolecular FÖRSTER Resonance Energy Transfer for Singlet Fission

In recent years, carbon materials are widely investigated because of their extraordinary chemical, electrical and physical properties. But most of the researchers utilizes graphite, graphene, reduced graphene oxide (rGO), carbon nanotubes (CNT), etc., as carbon material due to their excellent aforsaid properties.   Keeping this in mind, we have syntheized the candle carbon soot using candle flame at room temperture conditions. We have  observed that a simple flame of candle is used to synthesize the layers of carbon soot  on desired substrate. This synthesis method has become an alternative rote for the preparation of carbon nanomaterials because of its advantages of low cost and mass production. Also, we have investigated , the acid treatment of candle soot is drastically improved their structural and electrical  properties as compared to as-synthesized soot. The effect of  acid functionalization on the  candle soot structure were investigated by X-ray diffraction (XRD) and Raman spectroscopy. This material has potential application in battery, photovoltaic cell, electronics and sensor. 

Nanostructures of graphene demonstrate a wide range of optical, electronic, and magnetic properties depending on their size and chemical structures, which renders them promising as next-generation carbon-based nanomaterials, e.g., for nanoelectronics, spintronics, photonics, and solar energy conversion. Large polycyclic aromatic hydrocarbons (PAHs) possess the nanoscale graphene structures and have demonstrated the unique optoelectronic and magnetic properties predicted theory, thus attracting renewed attentions as atomically precise nanographenes [1]. We have recently developed the synthesis of dibenzo[hi,st]ovalene (DBOV) as a nanographene with a combination of zigzag and armchair edges, which demonstrated high stability, strong red emission, and optical gain properties [2]. The post-synthetic edge-functionalization of DBOV could be achieved through regioselective bromination, enabling the introduction of various substituents for modulating the optoelectronic and photophysical properties. For example, functionalization of DBOV with two fluoranthene imide (FAI) groups induced red-shift of the absorption and emission bands, increase of the Stokes shift, and enhancement of the stimulated emission (SE) signals with significantly reduced excited state absorption, allowing the efficient lasing at 720 nm [3]. On the other hand, we have more recently synthesized other unprecedented nanographenes with armchair, zigzag, and fjord edges, such as dibenzo[a,m]dinaphtho[3,2,1-ef:1',2',3'-hi]coronene (DBDNC), showing nonplanar structures by the single-crystal X-ray [4,5]. Notably, DBDNC displayed a SE signal at 710 nm with a longer lifetime than that of DBOV, presumably due to the suppression of intermolecular interactions. These results provide a further insight into the relationship between the PAH structures and their photophysical properties, paving the way toward their photonic applications.

The possible utilization of biological nano-logic circuits in the integration and regulation of DNA repair, and their potential use by cells in rapid sub-second decision making and calculations are discussed. Given advantages of logic type control, one would expect that if it hadn't arisen the during the initial abiotic phase of evolution, then it would have arisen to control at least some biological processes over the next approximately 3 billion years of evolution, where single celled life was likely the only form of life on Earth. Several of the required components have been identified in cells, such as biological concentration oscillations, which behave as an analogue of the square wave time base in electronic sequential digital circuits, and at least one phosphologic gate. Globular protein logic gates would be ~10% of the size, in terms of their linear dimensions (1/1000th of the volume), of their smallest current electronic counterparts. The study of the control of cellular data processing pathways will reveal the relative importance of analog versus digital control. These future studies will likely give rise to the tools necessary to therapeutically exploit this information.

Kesterite Cu₂ZnSnS₄ for prospective applications in photovoltaic (PV) cells is a complex quaternary metal sulfide semiconductor that as a tetragonal polytype shows the advantageous energy band gap E_g of 1.3-1.5 eV. Yet, from a practical viewpoint, not much is know about the compound’s susceptibility to oxidation in air which can impact its synthesis and characterization as well as stability in the application/storage stages.

One of the kesterite materials forms are nanopowders that can be used to make special inks or as sputtering targets in PV cell preparations. We recently developed a few precursor systems for the preparation of kesterite nanopowders by the mechanochemically assisted synthesis method. The isolated raw nanopowder from the synthesis in all cases is a cubic polytype of kesterite (tentatively called prekesterite) that does not show semiconductor properties. Only, after annealing under a neutral gas atmosphere at 500 °C this form is converted to the tetragonal kesterite semiconductor.

In this study, both the raw prekesterite and annealed kesterite nanopowders were synthesized from three precursor systems [1,2], i.e., from the mixture of the (i) component elements (CE) {2Cu+Zn+Sn+4S}, (ii) selected metal sulfides and sulfur (MS) {Cu₂S+ZnS+SnS+S}, and (iii) from in-situ made Zn/Sn copper alloys that were further reacted with sulfur (CA) {2Cu+Zn+Sn} → Zn/Sn copper alloys+4S}. The resulting black powders were investigated as freshly made and after a 6-month exposure to ambient air.

The X-ray photoelectron spectroscopy XPS confirmed in all nanopowders the characteristic binding energies of copper Cu(I), zinc Zn(II), tin Sn(IV), and sulfur S (in sulfides) as expected in both kesterite polytypes. However, for the air-exposed samples the S 2p region contained a set of two additional peaks (S 2p_3/2 and S 2p_1/2) above 168 eV that are typical for sulfur binding energies in the sulfate -SO₄ groups. Their presence was confirmed by the analysis of the relevant oxygen O 1s peaks. The intensities of the sulfate-related peaks were higher for the prekesterites compared to the related kesterites, which pointed out to the higher oxidation reactivity of the former forms. This trend was further corroborated by the XRD patterns that confirmed substantial oxidation of all nanopowders after 6 months in air. The oxidation by-products in the amounts of up to several tens wt% included the hydrated forms of copper(II) and zinc(II) sulfates, and tin(IV) oxide SnO₂.

(NCN grant No. 2020/37/B/ST5/00151)